Reducing Errors in Health Care

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Translating Research Into Practice

Medical errors are responsible for injury in as many as 1 out of every 25 hospital patients; an estimated 48,000-98,000 patients die from medical errors each year. Errors in health care have been estimated to cost more than $5 million per year in a large teaching hospital, and preventable health care-related cost the economy from $17 to $29 billion each year.

Agency for Healthcare Research and Quality (AHRQ) research has shown that medical errors may result most frequently from systems errors—organization of health care delivery and how resources are provided in the delivery system.

Patients at Risk

An elderly woman with ambiguous symptoms (shortness of breath, abdominal pain, and dizziness) whose heart attack is not diagnosed by emergency room staff.

Errors like these are responsible for preventable injury in as many as 1 out of every 25 hospital patients1.

Errors in health care have been estimated to cost more than $5 million per year in a large teaching hospital2. According to a recent report by the Institute of Medicine (IOM)3, preventable health care-related injuries cost the economy from $17 to $29 billion annually, of which half are health care costs.

The IOM report3 estimates that 44,000 to 98,000 people each year die from medical errors. Even the lower estimate is higher than the annual mortality from motor vehicle accidents (43,458), breast cancer (42,297), or AIDS (16,516), thus making medical errors the eighth leading cause of death in the United States.

These and other findings of the IOM report are based on research sponsored by a variety of organizations, including the Agency for Healthcare Research and Quality (AHRQ).

For example, a study by AHRQ4 found that just one type of error—preventable adverse drug events—caused one out of five injuries or deaths per year to patients in the hospitals that were studied.

How Errors Occur

Errors can occur at any point in the health care delivery system, AHRQ-supported research has revealed.

Medication Errors

These are preventable mistakes in prescribing and delivering medication to patients, such as prescribing two or more drugs whose interaction is known to produce side effects or prescribing a drug to which the patient is known to be allergic.

Research by AHRQ-supported investigators is helping to characterize these errors (called preventable adverse drug events, or ADEs) and suggest how to prevent them.

In a study of inpatient care in two tertiary care hospitals5, errors in ordering and administering medicines accounted for 56 and 34 percent, respectively, of preventable adverse drug events.

Findings from a second study6 showed that dosage errors, in particular, were primarily due to the physician's lack of knowledge about the drug or about the patient for whom it was prescribed.

An attempt to identify risk factors for preventable adverse drug reactions among patients admitted to medical and surgical units at two large hospitals7 found few such factors, which suggested to the researchers that a focus on improving medication systems would prove more effective.

Surgical Errors

In contrast to ADEs, surgical adverse events (1 in 50 admissions in Colorado and Utah hospitals during 1992)8, accounted for two-thirds of all adverse events and 1 of 8 hospital deaths in a recent retrospective study of these institutions by an AHRQ fellow.

Diagnostic Inaccuracies

Incorrect diagnoses may lead to incorrect and ineffective treatment or unnecessary testing, which is costly and sometimes invasive. Also, inexperience with a technically difficult diagnostic procedure can affect the accuracy of the results. Here, too, AHRQ-funded researchers have made major contributions.

One study9 showed that physicians who performed 100 or more colposcopies (a test used to follow up abnormal Pap smears) a year had more accurate findings than physicians who performed the procedure less often.

Another study10 demonstrated that measuring blood pressure with the most commonly used type of equipment often gives incorrect readings that may lead to mismanagement of hypertension.

System Failures

Although errors in medication, surgery, and diagnosis are the easiest to detect, medical errors may result more frequently from the organization of health care delivery and the way that resources are provided to the delivery system. Research by AHRQ-supported scientists is helping to identify the systemic factors contributing to preventable adverse events.

Investigators in a major study6 discovered that failures at the system level were the real culprits in over three-fourths of adverse drug events.

Failures in disseminating pharmaceutical information, in checking drug doses and patient identities, and in making patient information available are system errors that accounted for adverse drug events in over half of the hospitals studied.

One system-level factor, staffing levels of nurses (adjusted for hospital characteristics), was found in a study11 to influence the incidence of adverse events following major surgery, such as urinary tract infections, pneumonia, thrombosis, and pulmonary compromise.

This research on systemic problems leads investigators to conclude that any effort to reduce medical errors in an organization requires changes to the system design, including possible reorganization of resources by top-level management.

Improving Patient Safety

Research funded by AHRQ and others has been important in identifying the extent and causes of errors. Now, additional research is needed to develop and test better ways to prevent errors, often by reducing the reliance on human memory. Some areas of past research that have shown promise in helping to reduce errors include computerized ADE monitoring, computer-generated reminders for followup testing, and standardized protocols.

Computerized ADE Monitoring

Although chart review was found in an AHRQ-funded study12 to be more accurate than computer tracking and voluntary reporting in identifying adverse drug events, it required five times more personnel time. Researchers concluded that the computerized method was the most efficient means of tracking drug errors.

Computer-Generated Reminders for Followup Testing

Some diagnostic tests must be repeated to follow up certain conditions, but a small number of such repeat tests are done too early to yield useful results. In contrast, laboratory results showing that a patient needs critical care may not be communicated in a timely manner.

One study funded by AHRQ13 found that a computerized reminder system to alert physicians to the proper timing of repeat tests reduced the number of patients who were subjected to unnecessary repeat testing.

The same research group subsequently reported14 that an automatic alerting system for communicating critical laboratory results reduced the time until appropriate treatment when compared with the existing hospital paging system.

Standardized Protocols

An AHRQ-sponsored study15 of patients in intensive care units who had severe respiratory disease found a four-fold increase in survival rate with the use of computerized treatment protocols.

Still other investigators are testing computerized decision support systems in various patient populations. All of these research efforts reflect AHRQ's commitment to improving patient safety by providing new tools to augment provider judgment.

AHRQ-funded research continues to create and test methods to help clinicians avoid errors in health care delivery. An investigation funded by AHRQ and the National Institute on Aging will address the incidence and preventability of adverse drug events in elderly patients receiving ambulatory care.

The Agency has recently funded four Centers for Education and Research in Therapeutics (CERTs)16 as part of a 3-year demonstration program. The CERTs will conduct research to increase understanding of ways to improve the appropriate and effective use of drugs, biologicals, and devices in treatments and to avoid adverse events. These centers will also add to our knowledge of the possible risks of new uses of drugs, and combinations of drugs, as they are prescribed in everyday practice.

In addition, the Agency has recently announced17 that it will enter into cooperative agreements with nonprofit and for-profit health care organizations to test the effectiveness of the transfer and application of systems-based best practices to reduce medical errors and improve patient safety. This research will help identify high-risk patients or patient groups, providers, health care processes and settings, as well as developing generalizable methods for error reduction.

Promoting Safety

AHRQ (then known as AHCPR, the Agency for Health Care Policy and Research) supported the conference "Enhancing Patient Safety and Reducing Errors in Health Care," which launched the National Patient Safety Foundation.

AHRQ also works with partners, such as the National Committee on Patient Information and Education (NCPIE), to promote patient awareness of medication safety. In 1997, AHCPR and NCPIE co-sponsored the publication of a consumer guide, Prescription Medicines and You, to help consumers understand how to avoid errors in taking medicines.

In sum, AHRQ's contributions have resulted in a broader understanding of the nature of patient safety problems and where they occur in the delivery of health care. AHRQ-supported research is in the forefront of a rethinking of health care systems to reduce medical errors.

More information on AHRQ medical errors research is online. You also may contact: